JPH0627298A - Monochromatic same phase x-ray condenser - Google Patents

Abstract

PURPOSE:To eliminate influence for scattering X-rays caused by total reflection as much as possible in the case where X-rays are made incident at a low incident angle not much exceeding a critical angle for a crystalline material for the purpose of obtaining good monochromatic same phase X-rays. CONSTITUTION:A plurality of multi-layer films 11, 12 made of a crystalline material are opposed to each other and arranged at a position where X-rays 13 of an incident angle alpha close to a critical angle are reflected and allowed to interfere at the same incident angle alpha successively and the only X-rays which satisfy an interference condition out of the X-rays 13 successively made incident on the multilayer films 11, 12 are taken out successively. Thereby their intensity becomes small, their scattering light components are taken away gradually, and finally same phase X-rays can be taken out with monochromatic light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monochromatic light for spectroscopy in which X-rays are incident at an incident angle close to the critical angle of a substance to cause reflection interference to condense monochromatic X-rays of the same phase. It relates to an in-phase X-ray concentrator.

[0002]

2. Description of the Related Art Generally, X-rays have a short wavelength (several 10 Å ~
The index of refraction of the material is almost equal to 1. When such X-rays are incident on the solid surface at a grazing angle, total reflection occurs. The critical angle θc is usually about 10 to 30 ′, and the longer the wavelength of X-ray, the larger. A curved mirror is used for light collection by utilizing this total reflection. Also, X
The lines show interference phenomena like light, and when the phases are aligned, the waves strengthen each other. By the way, as shown in FIG. 5, when the X-ray 1 is incident on the surface of the substance 3 on the substrate 2 at a grazing incidence angle α, the wave reflected on the surface of the substance 3 and the wave reflected on the surface of the substrate 2 are different from each other. , The phases are aligned at a certain angle α ₁ having a relationship as shown in FIG. This occurs when the optical path difference between the two X-rays equals an integer multiple of the incident X-ray wavelength. Point P indicates a peak due to interference. Here, substance 3
If the film thickness is less than 3000 Å or less, the X-ray 1 does not reach the substrate 2 and this phenomenon does not occur. The substance 3 may be crystalline or amorphous, and the point is that it is uniform.

By the way, if the film thickness of the substance 3 is less than 3000 Å and it is provided in a multi-layer structure, the above-mentioned interference effect is increased. However, the layers must be mirror-finished. However, according to the current manufacturing technology, it is possible to provide several thin film layers uniformly. For example, LB
GaAs provided by film or MBE (Molecular Beam Epitaxy)
It is possible with semiconductors such as. When the incident angle α is α ₁ , the reflected X-rays are monochromatic (spectralized) according to the above-mentioned principle and have the same phase.

[0004]

However, in practice, as shown in FIG. 7, at the incident angle α ₁ , in addition to the monochromatic and in-phase X-ray components, the wavelength and phase of the substance 3 scattered by the surface of the substance 3 and the like are scattered. Different X-ray components (shown by hatching in the figure) also occur at the same time, and they are not separated into X-rays of perfect monochromatic / in-phase.

[0005]

Means for Solving the Problems X at an incident angle close to the critical angle
A plurality of multi-layered films made of a crystalline material were arranged facing each other at positions where the lines were sequentially reflected and interfered at the same incident angle.

[0006]

Since only X-rays that satisfy the interference condition are sequentially extracted from the X-rays that are successively incident on the surfaces of a plurality of multilayer films, the intensity of the X-rays becomes small if they are interfered many times, but the scattered light component is gradually removed. Finally, monochromatic light is extracted as X-rays of the same phase.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In this embodiment, a plurality of, for example, two multilayer films 11 and 12 are arranged with their surfaces facing each other, and the X-ray 13 is sequentially reflected and interfered between these surfaces. Here, the multilayer film 11 is sequentially laminated on the substrate 14 in a state having the atomic plane 15. Similarly, the multilayer film 12 is also formed by sequentially stacking on the substrate 16 in a state having the atomic planes 17.

As a method of manufacturing the multilayer film 11 (similar to the multilayer film 12), as shown in FIG. 2, the material layers A and B of different atoms or different molecules are formed on the substrate 14 by A, B, A,
It may be laminated as in B ,. Here, the material layers A and B
May have the same or different film thickness. When the film thickness is different, two vibrations having different periods of the peak P due to the interference shown in FIG. 6 are generated, so that the film thickness relationship such as A = 2B may be adopted. For the same reason, a structure in which three or more layers are sequentially stacked or a structure including only the A layer may be used. Further, in the material layers A and B, it is preferable that the difference in density between the two is large because the vibration (peak) increases. Although the total thickness of the multilayer film 11 depends on the atomic species used, it may be 5000 Å or less so that it does not penetrate. If the thickness of each layer itself becomes too thin, the vibration cycle becomes smaller, so
About 0 to 500Å is suitable. The surface of the multilayer film 11 is 3 to
It is preferable that the roughness is about 10Å because scattered light is reduced. It is preferable that the incident angle α of the X-ray 13 is as close to the critical angle as possible and that the peak appears. At this time, X-ray 1
Since the incident angle α can be increased as the wavelength of 3 is longer, the setting becomes easier. Also, the atomic plane 1 for diffracting
Since 5 may be a single crystal surface or a surface in which molecules are laminated in layers such as an LB film, the expression “crystalline material” is used in the present invention. When two or more kinds of substances having different densities are laminated, the substances to be laminated are not the same, and the interference effect becomes large, and the X-ray having high intensity can be obtained. The material of the substrate 14 for the multilayer film 11 is not particularly limited, such as glass, Si, SiO ₂ and a metal thin plate.

Therefore, as shown in FIG. ₁ , the angle is fixed to the X-ray incident angle α ₁ which is increased by the interference, and the multilayer film 11,
When 12 are faced so that the incident angles α of the X-rays 13 are the same, only the X-rays 13 satisfying the interference condition are sequentially extracted. Therefore, although the X-ray intensity is reduced by causing interference a number of times, the scattered light is gradually removed and the interference is repeated, so that only monochromatic light having the same phase is extracted. At this time, even if X-rays that spread as in the illustrated example are used, only the interfering X-rays are extracted, so that the width of the X-rays 13 becomes narrow and the X-rays 13 are condensed.
The number of times of interference varies depending on the intended intensity and the degree of monochromaticity, but is preferably about 2 to 6 times.

Now, a specific example will be described. First, S
Using an ion beam sputtering device on the i-wafer substrate,
The following conditions Target: Si, Cu Substrate heating: None Ionized gas: Ar (99.999%) Ion gun current x voltage: 3 mA x 9 kV Ion incident angle: 30 ° Base pressure: 3 x 10 to ⁷ Torr Target-substrate Distance: 15 mm Substrate size: 4 inch diameter circle Thickness of each layer: 200 Å (1 for both Si and Cu
Three layers each having a laminated film thickness structure of about 4000 Å with Si 2 as the outermost surface were prepared.

Then, with respect to one of such multi-layer films, an X-ray apparatus RU-300 manufactured by Rigaku Co., Ltd. was used (target is Cu), and Cu was dispersed by Si (111).
When the relationship between the incident angle of Kα rays and the intensity was obtained, a large peak was obtained when the incident angle was about 7 mrad.
In this case, the background (hatched area shown in Fig. 7)
The intensity ratio between the peak and the peak was 1/1. The X-ray was further rocked using a Si (111) crystal, and the half-width was calculated to be 21 seconds.
A good monochromatic X-ray was obtained.

Further, the multilayer film formed on the Si wafer substrate is faced to the multilayer film so that the incident angles of X-rays are the same, and the multilayer film is arranged so as to be reflected twice and the peak value is obtained. The intensity ratio between the background and the peak top is about 1/2. Further, the half width obtained from the rocking curve is 16 seconds.

Next, regarding the third multilayer film,
When the peak value was obtained by arranging the second multilayer film so as to be in a staggered arrangement with the second multilayer film (the incident angle of X-rays is the same) and reflecting three times, the background value was obtained. The intensity ratio between the peak and the peak top is about 1/4. Further, the half width obtained from the rocking curve is 12 seconds.

As described above, as the number of times the multilayer film is used increases, the width of X-rays decreases (that is, the light is condensed), the background decreases, and the X-ray components in phase increase. Since the full width at half maximum of is reduced, the monochromaticity is improved.

As a result of the method of this embodiment, the influence of scattered X-rays and the like as shown by hatching in FIG. 7 is alleviated,
The characteristics as shown in FIG. 3 are obtained, and the X-ray becomes excellent in monochromatic in-phase property.

If the substrate and atomic plane can be made uniform and arbitrarily long, as shown in FIG. 1, the upper and lower multi-layer films 11 and 12 alone are used.
You may make it reflect many times between these. Further, in FIG. 1, if the thin film layers can be laminated on the substrate 16 in a uniform and thick laminated state, as shown in FIG. 4, the multilayer film 12 can be formed without using the multilayer film 11 side. X-ray passage 1 which is cut out in a U shape when viewed from the side
8 may be formed (the upper and lower surfaces form a plurality of multilayer films 12a and 12b), and this structure is more likely to have the same angle.

By the way, unless X-rays are incident at an incident angle very close to the critical angle of the crystalline material, the atomic plane (diffraction plane) and the cut surface (surface) of the crystal may be formed so as to be offset from each other. , "Bragg case asymmetrical reflection" is conventionally known. That is, as shown in FIG. 8, in the crystalline material 20 having a single crystal structure, its atomic plane 21 and cut plane 22 are
And the X-ray 23 are formed as shown in FIG.
To make the X-ray width reflected by making the cut surface 22 incident on the cut surface 22 smaller, and make the X-ray width reflected by making the X-ray 23 incident on the cut surface smaller as shown in FIG. Used. That is, the X-ray 23 is reflected by the atomic plane (diffraction plane) 21 and interferes by satisfying the Bragg condition, as in the case of the method of the present invention. However, since it is used at an incident angle larger than the critical angle, the total reflection that is the premise of the present invention is irrelevant, and there is no problem of reducing the total reflected light.

The device of the present invention, which functions as an X-ray spectroscope, is called an X-ray concentrator for the following reason. At present, X-rays can be obtained only by divergent light, and those using general X-ray tubes and rotor targets, those using plasma, and those using radiant light are all divergent. Then, in the case of spectral separation, the beam width becomes wider in the case of FIG. 8A, whereas in the case of FIG. 8B, only the light satisfying the diffraction condition is reflected, so that the beam width becomes the incident beam. Since the beam width is narrower than the width, the beam width can be narrowed by the spectrum itself. However, according to the configuration of this embodiment, the beam width is narrowed to a narrower state and reflected. It was done.

Further, the reflecting mirror for soft X-rays (wavelength of 3 to 100Å) is used as a reflecting mirror at a larger angle (about 45 °) by laminating two kinds of materials having a large difference in density. However, if this embodiment is applied, it can be applied to a larger angle.

[0020]

As described above, according to the present invention, a plurality of multilayer films made of a crystalline material are arranged to face each other at a position where X-rays having an incident angle close to the critical angle are sequentially reflected and interfered at the same incident angle. Since only the X-rays that satisfy the interference condition are sequentially extracted from the X-rays that are sequentially incident on the surface of the multilayer film, the scattered light component can be gradually removed though the intensity decreases when the interference is repeated many times. Specifically, monochromatic light can be extracted as X-rays having the same phase.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing a laminated structure.

FIG. 3 is an incident angle-X-ray intensity characteristic diagram.

FIG. 4 is a schematic diagram showing a modified example.

FIG. 5 is a schematic view showing the principle of low incidence angle X-ray intensity measurement.

FIG. 6 is an incident angle-X-ray intensity characteristic diagram.

FIG. 7 is an incident angle-X-ray intensity characteristic diagram showing an extracted single-color in-phase portion.

FIG. 8 is a schematic diagram showing the principle of asymmetric reflection in the case of the conventional high incidence angle method.

[Explanation of symbols]

 11,12 Multilayer film 13 X-ray

Claims (1)

[Claims] 1. A monochromatic in-phase X-ray condensing device, wherein a plurality of multilayer films made of a crystalline material are arranged facing each other at positions where X-rays having an incident angle close to a critical angle are sequentially reflected and interfered at the same incident angle. vessel.